This invention relates to a cup type formation packer shoe to be used in cementing wells. In wells for the production of oil and gas the casing cemented into the bore hole will wear out and leak due to corrosion, wear from various well operations, etc. and need to be repaired. The casing is then typically repaired by cementing a smaller string of casing inside the first.
When cementing the smaller string of casing in the first, it is common to use a formation packer shoe on the bottom of the smaller string of casing to control the cement during the cementing operation. Such a typical prior art formation packer shoe is shown and described in Halliburton Services Sales and Service Catalog, Number 43 on pages 2437, 2438 and 2439 therein.
However, in wells which have a low level of fluid therein and in which it is desired to cement a full string of smaller casing in the well to repair the existing casing in the well, the differential pressure across the packer portion of the formation packer shoe often exceeds the typical 1000 psi differential pressure rating of the packer on the inflatable packer shoe. In these wells it is necessary to use a formation packer shoe which will withstand the higher differential fluid pressures necessary to cement the full string of casing in the existing casing in a single operation.